Improvement in lock safety-valves for steam-boilers



H. G.YASHTON.

Improvement in Lock Safety Valves for Steam Boilers.

Patented Feb.13 1872.

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an, M r Insane/v53 rnaozss a tubular valve-seat, D, having HENRY G.ASHTON, OF EAST CAMBRIDGE, MASSACHUSETTS.

IMPROVEMENT IN LOCK SAFETY-VALVES FOR STEAM-BOILERS.

Specification forming part of Letters Patent No. 123,546, dated February13, 1872.

To allpersons to whom tizesepresents may come:

Be it known that I, HENRY G. ASHTON, of East Cambridge, of the county ofMiddlesex and State of Massachusetts, have invented an Improved LockSafety-Valve for Steam-Boilers and do hereby declare the same to befully described in the following specification, and represented in theaccompanying drawing, of Which- Figure 1 is a front elevation, and'Fig.2 a vertical section of it, it being shown as applied to a hollowstandard or educt, A, to be fixed to the top of a boiler.

The case B is cylindrical; is screwed upon the standard, as shown at aa; has a series of long slots or openings, 1) I), made verticallythrough it; and is surmounted by a circular cap, O,provided with a knobor handle, 0. Furthermore, there is arranged concentrically within thestandard A and at its upper part, or applied thereto, in manner as shownin Fig. 2, a cylindrical valve, E, which has a cylindrical extension,(I, provided with a semi-spherical open chamber, 6. A guide-cylinder, F,closed at top and formed as shown, is screwed at its top, as representedat e 0, into the upper part of the case B, and extends downward nearlyto the valveseat, and encompasses and fits to the cylindrical part ofthe valve, all being as shown. From and concentrically with the cap 0 aey lindrical journal, f, is projected downward through a correspondinghole, g, made in the head of the guide-cylinder F, and is connected.with the said head by a nut, h, screwed upon the journal. Furthermore,there extends down from such journal a male screw, G, which is screwedinto and through a nut or cap, H, between and against which and thevalve, and within the cylinder F, there is arranged ahelical spring, I.By taking hold of the knob c and revolving the cap 0 the nut or cap Hmay be depressed or raised within the cylinder F so as to vary thepressure of the spring upon the valve. A bolt, K, goes through the cap Oand the flange a; of the case B, such bolt being provided with an eye orhole going transversely through its lower part to receive the hasp of apadlock, L. The said cap C may or should be provided with a series ofholes made down through it at or about at equal distances apart, so asto admit of the cap 0 being fixed or looked after it may have beenadjusted, to cause the spring to operate with any desired degree ofpressure on the valve. If desirable, such holes may be marked orstamped, or provided with marks or numbers, to indicate the pressure inpounds per square inch of the spring on the safety-valve, when the boltmay be in either of such holes of the flange. The space between thebottom of the insulator and guide F and the valve-seat D will admit ofthe escape of steam into the case B and out of its openings 1) when thevalve is forced ofi' its seat. The purpose of said part F is not only toguide the valve vertically, but to insulate the spring and itscontractile mechanism from the steam, as well as to prevent any personfrom gaining access to the spring and its cap'nut when the cap 0 islocked down.

I am aware of the safety-valves shown and described in the United Statespatents 81,320, 86,346, and 97 ,472, and make no claim thereto oranything contained therein. Neither of such valves has to its case arotary cover with a screw -projected fiom it, as in my safetyvalve; norhas either of the said patented valves a guard, F, screwed into-theouter case and separate from the valve, and serving as a bearing for thescrew-journal and its rotary cover; nor is there in said patented valvesthe arrangement of the guard as a guide for the valve, and at a shortdistance on" its seat, as is shown in my lock-up safety-valve. Thereforemy said valve differs in essential particulars from the others, asstated.

- I claim- The case B, the rotary cap 0, the valve E, its seat D, theinsulator F, the spring I, the screw G, and the cap-nut H, allconstructed, arranged, and applied together substantially in manner asexplained.

HENRY G. ASHTON.

Witnesses:

B. H. EDDY, J. R. Snow.

